I don't know much about the shelters cause I have never stayed in one. I think it's a floor and you don't need a tent but I'm not sure! Don't leave your tent behind just yet...
You need to go to the link 'Jirisan' from my previous posts, look at the map and see what shelter you want to camp in and then call and make reservations for that shelter. The numbers are all on the website.
Fall: To retreat in dynamic fashion from a climb.